Life Cycle Assessment (or LCA) is a technique to quantitatively assess the environmental impact and the energy requirements
of a product or service from its initial raw materials to its final disposal (i.e. cradle to grave). This assessment takes
into account any other products or services that may be required to facilitate its use and/or production.

One of the key advantages of using LCA is it allows a direct and fair comparison between two products or services with
regards to the environmental and energy impact. In LCA every relevant detail is taken into consideration. This encompasses
the distance the raw materials have to be exported to the type of packaging that is used to house the final product.

The level of detail achieved and the quality of the information used determines the accuracy of the assessment. Due to this
kind of comparative assessment LCA is an excellent tool to weigh costs and benefits and is therefore a useful aid in
decision-making and policy analysis.

When considering LCA for biofuels, it must take into account the evaluation of the energy and global warming costs of
producing biodiesel from energy crops in the UK and comparing this with other fuels and relevant energy saving measures.

Due to the very complex nature of LCA and the fact that so many different factors need to be taken into account we have
lacked the time and resources to conduct our own life cycle assessment and so are relying on other work carried out in
this area.

The details of this section are based on a report commissioned by DEFRA and carried out by the Resources Research Unit of
Sheffield Hallam University in January 2003. The report entitled “Evaluation Of The Comparative Energy, Global Warming
And Socio-Economic Costs And Benefits Of Biodiesel” produced a life cycle assessment for Biodiesel based on already
existing studies, taking the most relevant data for Biodiesel production in the UK. (REF23)

The Resources Research Unit performed two assessments for biodiesel production. One where the biodiesel is produced using
more conventional means and one where it is produced using a modified production. This modified production used low
nitrogen methods of cultivation. It also uses the rapeseed straw as an alternative heating fuel for the drying, solvent
extraction, refining and esterification process. And finally it uses biodiesel as the fuel for agricultural machinery
and transportation.

The following report will only detail the conventional production in an attempt to be reasonably conservative. If you
interested in reading the report for yourself then you can find it
here .

Since biodiesel can be described as ‘carbon neutral’ then any CO2 emissions associated with it must come from a source
outside that of combustion of the fuel. In fact there are many sources of CO2 associated with biodiesel production.
Most of the emissions come from the esterification process, the production of fertilizer and the extraction of the oil
from the seed. These CO2 emissions are not always produced directly from the process but taken from the energy requirement.
What this means is that the energy a process uses has an associated emission. For example electricity used in the
esterification process may well come from a coal power plant, so the amount of electricity used can be related to the
amount of CO2 released from the plant.

It was found that for every ton of biodiesel produced 916 ± 52 kg CO2 was released into the atmosphere. The chart below
shows the proportions of where these emissions come from.

Representative Carbon Dioxide Outputs for Biodiesel by
Conventional Production from Oilseed Rape in the United Kingdom

GHG emissions can be calculated in just the same way as for CO2 emissions. In order to group these emissions together
each kg of GHG has an equivalent mass of CO2 based on the 100-year global warming potential.

For each ton of biodiesel produced the equivalent of 1,516 ± 88 kg of CO2 are released.

By quantifying the amount of energy required to produce biodiesel it is possible not only to see what processes require
the most energy but also to establish an energy balance over the life cycle. I.e. the energy you get out against the
energy you put in.

For every ton of biodiesel produced 16,269 ± 896 MJ of energy is required.

The chart below shows how this is broken down.

Representative Primary Energy Inputs for Biodiesel by
Conventional Production from Oilseed Rape in the United Kingdom

Not surprisingly the largest energy demands match up with the CO2 emissions.

A ton of biodiesel will contain around 40,800MJ of energy.

Energy Balance = Energy OUT / Energy IN
= 40,800 / 16.269
= 2.5

For these number to mean anything however there has to be something against which to compare them. In the case of
biodiesel this would be the LCA of fossil diesel.

CO2 Emissions
For each MJ of biodiesel produced 0.025Kg of CO2 is released.
For each MJ of fossil diesel produced 0.087Kg of CO2 is released.

>From this it is possible to work out the emissions savings from the introduction of biodiesel produced in the UK.
In the section on the quantitative biofuels production in the UK we worked out how much fossil diesel could be displaced
by growing rapeseed on half the setaside land in the UK. This land produced enough biodiesel to displace 2% of current
UK diesel consumption by volume.

Biodiesel has a lower energy content than fossil diesel so rather than find the emissions for biodiesel from the
volume being replaced it is more correct to find the emission from the energy being replaced, therefore:

Unfortunatly during the project we were unable to find a Life Cycle Assessment for bioethanol that was as good and as
transparent as the assessment we found for biodiesel.

What we did find however were figures produced by the United States Department of Energy’s National Renewable Energy Laboratory,
(NREL). These figures Stated that for every gallon of petrol that is displaced with bioethanol, then 7.3 Kg to 10 Kg of
carbon dioxide emission’s can be avoided (1.8-2.5 Kg of carbon equivalent) (REF38).

This is equivalent to 7.3kg to 10kg of CO2 displaced per 3.785412 litres of bioethanol.
Or 1.93kg to 2.64kg of CO2 displaced per litre of bioethanol.

If half the UK setaside land was used to produce bioethanol then around 1.395 billion litres of bioethanol would be produced.
If we are conservative and say 2Kg of CO2 are displaced then:

Total CO2 savings = 2 * 1.395 = 2.79 billion kg

This is equivalent to a 1.9% reduction in the UK's total CO2 emissions.